By the help of current technology developments, many useful functions that have been performed on various electronic apparatus are now possibly implemented on slim portable electronic device, such as smart mobile phones, tablets, or wearable devices. The functions include voice assistant, 3D imaging, mutual interactive, and so on. It is a trend for modern people to be keen on taking pictures and photos, and hence, imaging module has been a standard function for portable electronic device or apparatus. In plural functions of imaging module, zoom function is being favorite and popular by users because it performs different zoom in and out and different fields of views. However, it is difficult to have zoom function in imaging module for slim optoelectronic devices, e.g., smart phone. Their major limitation is the size or the thickness of the device.
FIG. 1 is a schematic cross-view diagram illustrating a present imaging module. Please refer to FIG. 1, a present imaging module 1 includes a lens assembly 11 and a sensor 12. The lens assembly 11 includes a housing 111, plural fixed lens elements 112, a movable lens element 113, an aperture 114, and a moving mechanism 115. The plural fixed lens elements 112 are fixedly accommodated within the housing 111. Compared to the fixed lens elements 112, the movable lens element 113 is coupled to the moving mechanism 115, moved by the moving mechanism 115, and movably accommodated within the housing 111. The aperture 114, which is capable of controlling the amount of light entering the lens assembly 11, is deposited at one side of the movable lens element 113 and on an optical axis 110 of the lens assembly 11. The sensor 12, which receives light passing through the plural fixed lens elements 112 and the movable lens element 113 and then images, is deposited at one side of the plural fixed lens elements 112 and the movable lens element 113, and aligned on the optical axis 110. Here, the movable lens 113 is inside the module, while the size of the whole module is fixed. This kind of zooming is named as “internally focusing” in literature. In general, there are several moving mechanisms inside a zooming module and hence, the size of the whole module will not be fixed.
FIG. 2 is a schematic cross-view diagram illustrating zooming process performed by a user's present imaging module. Please refer to FIG. 1 and FIG. 2, when an object is imaged by a present imaging module 1, outside light enters into the housing 111 and then passes through the fixed lens elements 112, the movable lens element 113, the other fixed lens elements 112, and the aperture 114 in sequence, and hence, reaches the sensor 12 to be imaged to form the image of the object. Provided that the object is located far away from the present imaging module 1, the user may take a picture for the object by using the zoom function of the present imaging module 1 that is also called zoom in/zoom out function. The operation procedure is illustrated as follows: the moving mechanism 115 is driven to shift the movable lens element 113 to a corresponding position shown in FIG. 2. Next, the outside light enters into the housing 111 and then passes through the fixed lens elements 112, the movable lens element 113, the other fixed lens elements 112, and the aperture 114 in sequence, and hence, reaches the sensor 12 to be imaged to form the zooming image of the object.
Besides, other present imaging module also includes a lens assembly and a sensor, and the lens assembly also includes a housing, plural fixed lens elements, a movable lens element, an aperture, and a moving mechanism. Compared to the one in FIG. 1 and FIG. 2, the moving mechanism of the other one is driven to shift the movable lens element in a direction vertical to the optical axis, and the zoom function is performed. However, such a design definitely forms the lens assembly with a bigger total width.
Zoom function is very important for imaging and photographing, however, zoom capability is subject to the total width or length of the lens assembly 11. The longer or wider the total length or width is, the bigger the zoom capability performs. On the other hand, the shorter or narrower the total length or width is, the smaller the zoom capability performs. Consequently, the zoom capability is improved with the increase in the total length and weight of the lens assembly, as well as the volume.
Accordingly, a lens assembly with better zoom capability and in a slim size is necessary for current demand in mobile electric device, module, or apparatus.